Optical tables are presently used in a wide variety of applications and environments. Commonly, the term optical table refers to any platform supporting vibration-sensitive equipment such as optical assemblies, biological experiments and/or equipment, or high-precision semiconductor manufacturing systems. Typical optical tables consist of at least one sandwich structure having two faceplates enclosing a lightweight honeycomb core. Due to low weight-to-stiffness ratios, these platforms find wide applications in optical research and high-precision manufacturing, usually in conjunction with soft pneumatic vibration isolators. Although good isolation from floor vibration can be achieved in these systems, the platform deviates from the ideal rigid-body behavior at natural frequencies of its flexural resonance vibrations. Those resonance vibrations may be mitigated by various types of dampers or damping systems.
While existing tuned dampers have proven useful in such applications, a number of design challenges remain. For example, a body serving as a moving mass of a damper may be required to move, in the frequency range of interest, linearly and uni-axially in the direction of modal vibration of the main structure, which may be in the normal (usually vertical) direction in case of an optical table. If the mass does not move in a prescribed manner, but rather exhibits rotational modes in the frequency range of interest, the damper may be ineffective. Further, manufacturing these devices has proven time-consuming as a hermetic seal is often required to ensure the damper fluid remains in place.
Further, the tuning characteristics of presently available tuned damper systems are often factory determined and set. As such, adjustments at a work site to correct for changing work environments or needs tends to be difficult if not impossible. Thus, in light of the foregoing, there is a need for tunable vibration damper systems for use with a variety of desired optical table assemblies, or the like, that are reliable, easily manufactured, easily adjusted or tuned and/or stable under varying temperatures.